An AC surface discharge panel as a representative plasma display panel (hereinafter, abbreviated as a “panel”) includes a front panel and a rear panel disposed facing each other and a large number of discharge cells between the front panel and the rear panel. The front panel has a plurality of display electrode pairs each including a pair of scan electrode and sustain electrode formed in parallel to each other on a front glass substrate thereof. A dielectric layer and a protective layer are formed so as to cover the display electrode pairs. The rear panel has a plurality of data electrodes formed in parallel to each other on a rear glass substrate thereof. A dielectric layer is formed so as to cover the data electrodes, and a plurality of barrier ribs are formed in parallel to the data electrodes further on the dielectric layer. On the surface of the dielectric layer and the side surface of the barrier ribs, a phosphor layer is formed. The front panel and the rear panel are disposed facing each other so that the display electrode pairs three-dimensionally intersect with the data electrodes, and the front panel and the rear panel are sealed with each other. In discharge space inside thereof, a discharge gas including, for example, 5% xenon in a partial pressure ratio is filled. Herein, a discharge cell is formed in a part where the display electrode pair and the data electrode face each other. In a panel having such a configuration, an ultraviolet ray is emitted by a gas discharge in each discharge cell. By using this ultraviolet ray, phosphor of each color, i.e., red, green and blue, is excited to emit light so as to carry out a color display.
As a method for driving the panel, a subfield method is generally used. The subfield method includes dividing one field period into a plurality of subfields and displaying a gradation by driving a combination of the subfields to emit light.
Each subfield includes an initialization period, a writing period and a sustain period. In the initialization period, an initialization discharge is generated so as to form a wall charge necessary for the following writing operation on each electrode. The initialization operation includes an initialization operation for generating an initialization discharge in all discharge cells (hereinafter, abbreviated as an “all-cell initialization operation”) and an initialization operation for generating an initialization discharge in a discharge cell in which a sustain discharge has been carried out (hereinafter, abbreviated as a “selective initialization operation”).
In the writing period, a writing pulse voltage is selectively applied to a discharge cell to be displayed so as to generate a writing discharge and to form a wall charge (hereinafter, this operation is also referred to as “writing”). Then, in the sustain period, a sustain pulse is applied to the display electrode pair including the scan electrode and the sustain electrode alternately and a sustain discharge is generated in a discharge cell in which a writing discharge has been carried out. Thus, a phosphor layer of the corresponding discharge cell is allowed to emit light so as to carry out an image display.
Furthermore, among the subfield methods, a well-known method is a driving method in which an initialization discharge is carried out by using a gradually changing voltage waveform and further an initialization discharge is selectively carried out with respect to a discharge cell in which the sustain discharge has been carried out. Thereby, light emission that is not related to a gradation display is reduced as little as possible so as to improve a contrast ratio.
Specifically, the all-cell initialization operation for discharging all discharge cells in the initialization period of one subfield in the plurality of subfields is carried out, and the selective initialization operation for initializing only a discharge cell in which a sustain discharge has been initialized in the initialization period of the other subfields is carried out. As a result, light emission that is not related to a display is only light emission accompanied with a discharge in all-cell initialization operation, thus enabling an image display with a high contrast (see, for example, patent document 1).
By driving in this way, the brightness of a black display region changing depending upon light emission that does not relate to the image display is only weak light emission in the all-cell initialization operation, thus enabling an image display with a high contrast.
Recently, researches for developing a panel with a higher definition and a larger screen have been done. For example, when discharge cells are made to be fine in order to achieve a higher definition panel, the rate of a non-light emission region is increased, so that the brightness of light emitted per unit area tends to be reduced. In order to increase the brightness of emitted light, it is effective to increase the partial pressure ratio of xenon. However, if the partial pressure ratio is increased, a voltage necessary for writing is increased accordingly, thus making writing unstable. Furthermore, in a panel having a higher definition and a larger screen, the number of electrodes to be formed inside the panel is increased. Consequently, the pulse width of the writing pulse voltage has to be shortened in order not to increase the time necessary for writing. Thus, writing may be unstable.
When an addressing failure occurs due to these problems, a writing discharge is not generated in a discharge cell to be displayed, thus deteriorating the quality of image display.
[Patent document 1] Japanese Patent Unexamined Publication No. 2000-242224